

// Do this as the first thing so that any code reading it knows the right env.
process.env.BABEL_ENV = 'production'
process.env.NODE_ENV = 'production'

// Makes the script crash on unhandled rejections instead of silently
// ignoring them. In the future, promise rejections that are not handled will
// terminate the Node.js process with a non-zero exit code.
process.on('unhandledRejection', err => {
	throw err
})

// Ensure environment variables are read.
require('../config/env')


const path = require('path')
const chalk = require('react-dev-utils/chalk')
const fs = require('fs-extra')
const webpack = require('webpack')
const configFactory = require('../config/webpack.config')
const paths = require('../config/paths')
const checkRequiredFiles = require('react-dev-utils/checkRequiredFiles')
const formatWebpackMessages = require('react-dev-utils/formatWebpackMessages')
const printHostingInstructions = require('react-dev-utils/printHostingInstructions')
const FileSizeReporter = require('react-dev-utils/FileSizeReporter')
const printBuildError = require('react-dev-utils/printBuildError')

const measureFileSizesBeforeBuild =
  FileSizeReporter.measureFileSizesBeforeBuild
const printFileSizesAfterBuild = FileSizeReporter.printFileSizesAfterBuild
const useYarn = fs.existsSync(paths.yarnLockFile)

// These sizes are pretty large. We'll warn for bundles exceeding them.
const WARN_AFTER_BUNDLE_GZIP_SIZE = 512 * 1024
const WARN_AFTER_CHUNK_GZIP_SIZE = 1024 * 1024

const isInteractive = process.stdout.isTTY

// Warn and crash if required files are missing
if (!checkRequiredFiles([paths.appHtml, paths.appIndexJs])) {
	process.exit(1)
}

// Generate configuration
const config = configFactory('production')

// We require that you explicitly set browsers and do not fall back to
// browserslist defaults.
const { checkBrowsers } = require('react-dev-utils/browsersHelper')
checkBrowsers(paths.appPath, isInteractive)
	.then(() => {
		// First, read the current file sizes in build directory.
		// This lets us display how much they changed later.
		return measureFileSizesBeforeBuild(paths.appBuild)
	})
	.then(previousFileSizes => {
		// Remove all content but keep the directory so that
		// if you're in it, you don't end up in Trash
		fs.emptyDirSync(paths.appBuild)
		// Merge with the public folder
		copyPublicFolder()
		// Start the webpack build
		return build(previousFileSizes)
	})
	.then(
		({ stats, previousFileSizes, warnings }) => {
			if (warnings.length) {
				console.log(chalk.yellow('Compiled with warnings.\n'))
				console.log(warnings.join('\n\n'))
				console.log(
					'\nSearch for the ' +
            chalk.underline(chalk.yellow('keywords')) +
            ' to learn more about each warning.'
				)
				console.log(
					'To ignore, add ' +
            chalk.cyan('// eslint-disable-next-line') +
            ' to the line before.\n'
				)
			} else {
				console.log(chalk.green('Compiled successfully.\n'))
			}

			console.log('File sizes after gzip:\n')
			printFileSizesAfterBuild(
				stats,
				previousFileSizes,
				paths.appBuild,
				WARN_AFTER_BUNDLE_GZIP_SIZE,
				WARN_AFTER_CHUNK_GZIP_SIZE
			)
			console.log()

			const appPackage = require(paths.appPackageJson)
			const publicUrl = paths.publicUrl
			const publicPath = config.output.publicPath
			const buildFolder = path.relative(process.cwd(), paths.appBuild)
			printHostingInstructions(
				appPackage,
				publicUrl,
				publicPath,
				buildFolder,
				useYarn
			)
		},
		err => {
			const tscCompileOnError = process.env.TSC_COMPILE_ON_ERROR === 'true'
			if (tscCompileOnError) {
				console.log(chalk.yellow(
					'Compiled with the following type errors (you may want to check these before deploying your app):\n'
				))
				printBuildError(err)
			} else {
				console.log(chalk.red('Failed to compile.\n'))
				printBuildError(err)
				process.exit(1)
			}
		}
	)
	.catch(err => {
		if (err && err.message) {
			console.log(err.message)
		}
		process.exit(1)
	})

// Create the production build and print the deployment instructions.
function build (previousFileSizes) {
	// We used to support resolving modules according to `NODE_PATH`.
	// This now has been deprecated in favor of jsconfig/tsconfig.json
	// This lets you use absolute paths in imports inside large monorepos:
	if (process.env.NODE_PATH) {
		console.log(
			chalk.yellow(
				'Setting NODE_PATH to resolve modules absolutely has been deprecated in favor of setting baseUrl in jsconfig.json (or tsconfig.json if you are using TypeScript) and will be removed in a future major release of create-react-app.'
			)
		)
		console.log()
	}

	console.log('Creating an optimized production build...')

	const compiler = webpack(config)
	return new Promise((resolve, reject) => {
		compiler.run((err, stats) => {
			let messages
			if (err) {
				if (!err.message) {
					return reject(err)
				}
				messages = formatWebpackMessages({
					errors: [err.message],
					warnings: [],
				})
			} else {
				messages = formatWebpackMessages(
					stats.toJson({ all: false, warnings: true, errors: true })
				)
			}
			if (messages.errors.length) {
				// Only keep the first error. Others are often indicative
				// of the same problem, but confuse the reader with noise.
				if (messages.errors.length > 1) {
					messages.errors.length = 1
				}
				return reject(new Error(messages.errors.join('\n\n')))
			}
			if (
				process.env.CI &&
        (typeof process.env.CI !== 'string' ||
          process.env.CI.toLowerCase() !== 'false') &&
        messages.warnings.length
			) {
				console.log(
					chalk.yellow(
						'\nTreating warnings as errors because process.env.CI = true.\n' +
              'Most CI servers set it automatically.\n'
					)
				)
				return reject(new Error(messages.warnings.join('\n\n')))
			}

			return resolve({
				stats,
				previousFileSizes,
				warnings: messages.warnings,
			})
		})
	})
}

function copyPublicFolder () {
	fs.copySync(paths.appPublic, paths.appBuild, {
		dereference: true,
		filter: file => file !== paths.appHtml,
	})
}
